In detection systems of this type, ultrasound or microwave sensors are used, for example, for transmitting wireless signals and for detecting echo signals which are reflected by objects in the surroundings of the vehicle.
By ascertaining the propagation times of the signals and with the aid of different methods, a distance between the reflected objects and the sensors may be individually determined.
In many modern systems of the above-described type, a plurality of sensors is used for improving the detection range and the detection resolution with the objective of detecting the surroundings of the vehicle in all relevant directions.
German Patent Application No. DE 102005033403 A1 describes a conventional method for measuring distances, for example, using radar, lidar, or acoustic waves in which a signal propagation time is measured and analyzed. In order to accurately determine the propagation time, the reflected and detected signal is compared with a reference signal associated with the transmitted signal via correlation analysis, using a “matched filter.”
German Patent Application No. DE 19744185 A1 describes an ultrasound distance measuring system for a motor vehicle, in which a plurality of ultrasonic transducers is used. The simultaneous transmission of ultrasound pulses is used by making use of the superimposition and addition of corresponding wave amplitudes in order to achieve a more powerful transmission and thus greater detection ranges.
Great Britain Patent No. GB 2352294 A describes an ultrasound distance measuring system for motor vehicles in which transducers are operated consecutively at different frequencies in order to correct interferences or cancellations which may accidentally occur at certain frequencies, by operating at other frequencies.
German Patent Application No. DE 19963755 A1 describes a device for distance measurement for a motor vehicle in which a Plurality of distance sensors are provided which may be operated in different operating modes to improve the quality of measurement.
European Patent No. EP 0613428 B1 describes a bus system, in particular in a motor vehicle, which has a bus connecting a plurality of control units and in which the data transmitted on the bus are analyzed in a central device. Messages are output at a low transmission repeat frequency and extracted from the individual control units as needed.
U.S. Pat. No. 6,088,810 A1 describes a device for synchronized data transmission between spatially offset measuring devices or sensors or between these and a data processing device. The device includes a serial bus over which the components of the device communicate in two different operating modes.
U.S. Pat. No. 4,736,367 A1 describes a device for controlling and monitoring a plurality of relay circuits which are connected to the device via a single-wire bus system.
German Patent Application No. DE 102006021378 A1 describes a reverse drive sensor for a motor vehicle in which the function of a control unit for a plurality of sensors is assumed by a master sensor, which has, like similar, associated slave sensors, a microprocessor, and a transducer for transmitting and receiving ultrasound signals. The master sensor controls the timing for operating the slave sensors and for detecting the results.